| 摘要 |
PURPOSE: A fault diagnosis method is provided to diagnose faults of solenoid valve of motor vehicle transmission by using the change of state of frequency characteristics. CONSTITUTION: A fault diagnosis method comprises a step(S21) of detecting a voltage level of a feedback signal output terminal of a variable force solenoid valve; a step(S22) of judging whether the detected voltage level is at "on" state; a step(S23,S24) of increasing a short counter value by one, making a disconnection counter value zero, and judging the short counter value, if the detected voltage level is at "on" state; a step(S25) of generating a short fault code if the short counter value is greater than a first reference value; a step(S26,S27) of increasing the disconnection counter value by one, making the short counter value zero, and judging the disconnection counter value, if the detected voltage level is at "off" state; and a step(S28) of generating a disconnection fault code if the disconnection counter value is greater than a second reference value.
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